Electric switch



vAug. 2, 1932. A. E. f aRlsvx/QLD` ELECTRIC SWITCH Filed Jme 5, 1929 2 sheets-sheet 1 MAJ Q .39 HI KJ @Q QI@ ONU/0 3. r/Ll Fig my /0 QM C'. ZM

ATTORNEY Aug. 2, 1932. A. E. GRlswoLD ELECTRIC SWITCH 2 SheetS-SheefI 2 Filed June 5, 1929 f.' nlswo/d asf INVENTOR ATTORNEY A E N nd/ew JMCJWM H m l Patented Aug. 2, 1932- UNITED STATES PATENT OFFICE ANDREW E. GRISWOLD, OF SEATTLE, WASHINGTON, ASSIGNOR TO TRUMIBLI ELECTRIC MANUFACTURING COMPANY, PACIFIC CORPORATION OF WASHINGTON DIVISION, 0F SEATTLE, WASHINGTON, A

ELECTRIC SWITCH Application led June 3, 1929. Serial INO. 367,874.

My invention relates to improvements in electric switches, and the general object of my invention is to provide a dead front, plugin type, safety switch of novel and etlicient construction .in which the switch blades are carried on the cover plate of the switch receptacle and said cover plate is removable and is arranged to be turned end for end to selectively open or close the switch.

More specific objects are to provide a dead lfront safety switch which is especially designed for use in connection with household appliance circuits; to provide a switch which is foolproof and which has no exposed switch levers and in which the front surface of the switch is dead when the cover plate is removed.

Further specific objects are to provide a dead front safety switch of neat and compact construction, which is shallower and smaller than the ordinary switch of this nature, which is reliable and efficient in operation and which is ornamental and attractive in appearance.

Other and more specific objects will be apparent from the following description taken in connection with the accompanying drawings. 1 Y

In the accompanying drawings Figure 1 is a plan view showing the front of the switch with the cover plate applied so as to close the switch.

Fig. 2 is a similar View with the cover plate entirely removed.

Fig. 3 is a similar'view with the cover plate andthe block which shields the terminal clips entirely removed and other parts of the switch broken away.

Fig. 4 is a side elevation of the switch with the cover plate in place thereon.

Figs. 5 and 6 are sectional views substantially on broken lines 5--5 and 6-6 respectively of Fig. 3 the cover plate and block which shields the terminal clips being shown il?. these figures whereas they are removed in Fig. 7 is a detached perspective view of the cover plate. L

Fig. 8 is a detached plan view of block which shields the terminal clips.

vparts, Iv show a switch comprising a main frame 10 formed of insulating material, as fiber or bakelite, which may be provided with base bars 11 to adapt it to be secured within a cabinet or to any suitable support, not shown in the drawings.

The main frame is recessed on its front side, as sh'own, to aord a rectangularly shaped receptacle 12 in which a plurality of resilient split terminal clips "13,14, 15 and 16 may be mounted, the bottoms of said terminal clips being positioned in recesses 17in the bottom of the receptacle 12. The terminal clips 13, 14, l5 and 16 may be of conventional construction, as shown in Figs. 5 and 6, each formed of a single piece of spring metal bent double to leave a resilient loop-18 at the bottom and two upwardly extending blade engaging members which are spaced a short tween the terminal clips 13,145,15 and 16,1 provide two double pronged switch blades 20-20 and 21-21 which are secured by screws 22 to the inner side of a cover plate 23, each of said switch blades being of substantially the shape of a foreshortened letter U with the base flattened to rest squarely on the cover plate, and said switch blades being of unequal length, the distance between the prongs 21- -21 being greater than the corresponding distance between the prongs 20-20, the respective prongs 20-21 at one end of said two blades being in alignment transversely of the cover plate.

When the-cover plate 23is in one position the two prongs 20-20of the shorter switch blade will fit between the fingers of 'the two closer terminal clips 13 and 14 and thetwq 'large to receive said terminal clips.

prongs 21-21 of the longer switch blade willfit between the fingers of the two terminal clips 15 and 16 which are farther apart. When the cover plate is turned end for end onlyT the blade 2() of one blade member and the blade 21 of the otherblade member will lit between the two fingers of a terminal clip, the other prong of each switch blade being entirely out of alignment and out of contact with the companion terminal clip and the circuit through the switch-being broken.

The terminal clips 13, 14, 15 and 16 are covered and protected by a block 24 of insulating material which has recesses 25 suti'cierqitly arrower slots 26, just wide enough topermit the passage of the switch blades extend from the face of the block 24 inwardly and intersect the recesses 25. Two other narrow slots 27-27 extend from the face of the block 24 inwardly and are separate from the recesses 25 so that when the switch blades 20 and 21 are in said slots 27 and 27 they will be insulated from the terminal clips 13, 14, 15 and 16. A screw 28 is used to secure the block 24 to the bottom of the receptacle 12.

The words On and Off are inscribed on the face of the block 24 above and below the head of the screw 28 respectively and an opening 30 is provided in the cover 23 closer to one end of said cover plate than the other whereby said opening will register with, and expose to View, the word On when the cover plate is in the correct position to close the switch and will register with, and expose to view, the word Off when the cover plate is turned end for end into a position in which the switch is open.

The block 24 completely shields and protects the terminal clips 13, 14, 15 and 16 when the cover plate is removed so that it is impossible for the hands to come in contact with said terminal clips and it is therefore impossible for a person to inadvertentlyfreceive an electric shock off of this switch.

4When the cover plate is applied in either polsition it will completely close the front of the receptacle 12. When said cover plate is applied in one position it will closethe switch and when it is applied in the other position it will leave the switch open. When the cover plate is removed from the receptacle the switch will be left open. The ends of the block 24 are preferably cut away as at 31 to afford more convenient` access to fuse members 32 which may be placed in the ends of the recess 12. Other fuse members or plugs, not shown, may be placed in suitable receptacles 33 in a block 34 at the end of the switch frame 10 outside of the receptacle 12. Another block 35 may be rovided alongside of the block 34. Suitable binding posts 36 are provided on the switch housing 10 outside of the receptacle 12 and electrical conductors which are not shown recense' and which may be varied tov suit different conditions may connect the various termlnal clips, fuses and binding posts in any desired manner.

In the use of this switch, when the cover the blade member 21--21 which are farther apart will close the circuit between the other two terminals 15 and 16. When the cover plate is removed the circuit between both pairs of terminal clips will be broken and when said cover plate is turned end for end and replaced on the receptacle the blade members 20 and 21 will engage with the respective terminal clips 16 and 13 but the blade members 2U and 2l will enter the slots 27 and 27 respectively and will be insulated from all of the terminals. l/Vhen the cover plate is thus turned end for end, the hole 30 will register with, and show the Off sign.

Frictional engagement of the blade members with the terminal clips constitutes the only means for securing the cover plate 23 to the receptacle, it being apparent from the above description that when the cover plate is in the On position all four of said switch blades will be gripped by the terminal clips and when said cover plate is in the Oli position two of said switch blades, namely the diagonally opposite blades 20 and 21 will be frictionally engaged by the terminal clips.

The foregoing description and accompanying drawings clearly disclose what I now regard as a preferred embodiment of my invention but it will be understood that this disclosure is merely illustrative and such changes in the switch may be made as v'are fairly within the scope and spirit of the following claims.

I claim:

1. An electric switch embodying a receptacle, two pairs of resilient split terminal clips disposed within said receptacle, the two clips of one pair being spaced farther apart than the two clips of the other pair, a cover plate and two U shaped switch blade elements of different lengths secured to said cover` plate, both blades' of both switch blade elementssengaging said terminal clips and closingcircuits through said terminal clips in one position of said cover and one blade of each of said blade elements being clear of said terminal clips and leaving the circuits through said terminal clips open in another position of said cover.

2. An electric switch including a receptacle, two pairs of ,terminal clips wit-hin said receptacle, an insulating guard for said clips and having switch blade receiving slots therein, a two position cover `for said receptacle, two switch blades secured to said cover and having projecting ends for engaging and electrically connecting the respective pairs of said terminal clips when the cover is attached to said receptacle in one of its positions and for engaging one member of each pair of terminal clips without electrically connecting said clips when the cover is attached to said receptacle in its other position, the slots in said guard being positioned to receive the projecting ends of said blades in either position of the cover.

3. An electric switch including a receptacle, two pairs of terminal clips within said receptacle, an insulating guard for said clips and having switch blade receiving slots therein, a two position cover for said receptacle, two switch blades secured to said cover and having projecting ends for engaging and electrically connecting the respective pairs of said terminal clips when the cover is attached to said receptacle in one of its positions and for engaging one member of each pair of terminal clips without electrically connecting said clips when the cover is attached to said receptacle in its other position, the slots in said guard being positioned to receive the projecting ends of said blades in either position of the cover, and the two terminal clips of one pair of clips being spaced farther apart than the clips of the other pair and the projecting ends of one blade being spaced farther apart than the projecting ends of the other blade.

4. An electric switch including a receptacle, two pairs of terminal clips within said receptacle, a block of insulating material within said receptacle and having recesses to receive said terminal clips and constituting a protective housing for said clips, said block having a plurality of switch blade receiving slots, a two-position cover plate for said receptacle and two substantially U shaped' switch blades secured to said cover plate and adapted to enter some of said slots and engage said terminal clips and to electrically connect each respective pair of said clips when the cover plate is attached to said receptacle in one of its positions and said blades being adapted-to enter some of said slots and to frictionally en age one member of each pair of terminal c ips when the cover is attached to said receptacle in its other position.

5. An electric switch including a receptacle, pairs of terminal clips within said receptacle, a block of insulating materials for covering said clips and havin slots aiording access of switch blades to sai clips, said block being marked in two different locations to designate the on and off positions of the switch parts, a cover plate for said receptacle and adapted to be secured to vsaid receptacle in the on and oi positions of the switch parts and switch blades carried by said cover plate for electrically connecting each pair of said terminal clips when the cover plate is atto engage onemember of each pair of terminal clips when the cover plate is attached to the receptacle with the blades in the o' position, said cover plate having an opening to register with the on and oil' markings on said block to indicate the relative positions of the switch parts.

6. An electric switch including a receptacle, two pairs of resilient contacts within said receptacle, an insulating guard member for said contacts andhaving switch blade receiving slots therein, a removable cover for said receptacle and two projecting switch blades carried by said cover, the said cover being engageable with said receptacle in two positions and, in one of which positions, the switch blades are adapted to project through some of the slots in the guard member and into engagement with said contacts to retain the cover in position and to electrically connect the respective pairs of contacts and each of said blades being adapted, in the other position of said cover, to project through some of the slots in said guard member and into engagement with one member of each pair of contacts to retain the cover in position without electrically connecting the respective pairs of contacts. l

7. An electric switch including a receptacle, two pairs of stationary contacts within said receptacle, an insulating guard member for said contacts and having a plurality of switch blade receiving slots therein, a removable cover for said receptacle and two projectin switch blades carried by said cover, the said cover being reversible, end for end with respect to said receptacle and each of said blades being adapted, in one position of the cover, to project through some of the slots in said guard member to complete an electrical circuit through each respective pair of contacts and to retain the said cover in position and each blade being adapted, in the reversed position of said cover, to project through some of the slots in said guard member and into engagement with some of said stationary contacts to retain the cover in position without electrically connecting the respective pairs of stationary contacts.

The foregoing speciication signed at Seattle, Wash., this 15th day of May, 1929.

ANDREW E. GRISWOLD.

tached to the receptacle with the blades in the on position and said blades being adapted 

